The application of direct current bias has been the historical method of operating a photoconductor as a detector. However, direct current bias produces objectionable low frequency noise, limits dynamic range, and absorbs excessive power. Furthermore, the manufacturing technology used to produce an array of photoconductors inherently results in variations in resistance and response between the various photoconductors included in the array. This variation is so wide that there is little dynamic range left for employing the photoconductors as detectors.